AWS CloudFormation
User Guide (Version )

AWS::AutoScaling::AutoScalingGroup InstancesDistribution

InstancesDistribution is a subproperty of MixedInstancesPolicy that describes an instances distribution for an Auto Scaling group. The instances distribution specifies the distribution of On-Demand Instances and Spot Instances, the maximum price to pay for Spot Instances, and how the Auto Scaling group allocates instance types to fulfill On-Demand and Spot capacity.

For more information, see Auto Scaling Groups with Multiple Instance Types and Purchase Options in the Amazon EC2 Auto Scaling User Guide.

Syntax

To declare this entity in your AWS CloudFormation template, use the following syntax:

JSON

{ "OnDemandAllocationStrategy" : String, "OnDemandBaseCapacity" : Integer, "OnDemandPercentageAboveBaseCapacity" : Integer, "SpotAllocationStrategy" : String, "SpotInstancePools" : Integer, "SpotMaxPrice" : String }

Properties

OnDemandAllocationStrategy

Indicates how to allocate instance types to fulfill On-Demand capacity.

The only valid value is prioritized, which is also the default value. This strategy uses the order of instance type overrides for LaunchTemplate to define the launch priority of each instance type. The first instance type in the array is prioritized higher than the last. If all your On-Demand capacity cannot be fulfilled using your highest priority instance, then the Auto Scaling groups launches the remaining capacity using the second priority instance type, and so on.

Required: No

Type: String

Pattern: [\u0020-\uD7FF\uE000-\uFFFD\uD800\uDC00-\uDBFF\uDFFF\r\n\t]*

Update requires: No interruption

OnDemandBaseCapacity

The minimum amount of the Auto Scaling group's capacity that must be fulfilled by On-Demand Instances. This base portion is provisioned first as your group scales.

The default value is 0. If you leave this property set to 0, On-Demand Instances are launched as a percentage of the Auto Scaling group's desired capacity, per the OnDemandPercentageAboveBaseCapacity setting.

Required: No

Type: Integer

Update requires: No interruption

OnDemandPercentageAboveBaseCapacity

Controls the percentages of On-Demand Instances and Spot Instances for your additional capacity beyond OnDemandBaseCapacity.

The range is 0–100. The default value is 100. If you leave this property set to 100, the percentages are 100% for On-Demand Instances and 0% for Spot Instances.

Required: No

Type: Integer

Update requires: No interruption

SpotAllocationStrategy

Indicates how to allocate Spot capacity across Spot pools.

The only valid value is lowest-price, which is also the default value. The Auto Scaling group selects the cheapest Spot pools and evenly allocates your Spot capacity across the number of Spot pools that you specify.

Required: No

Type: String

Pattern: [\u0020-\uD7FF\uE000-\uFFFD\uD800\uDC00-\uDBFF\uDFFF\r\n\t]*

Update requires: No interruption

SpotInstancePools

The number of Spot pools to use to allocate your Spot capacity. The Spot pools are determined from the different instance types in the Overrides array of LaunchTemplate.

The range is 1–20 and the default is 2.

Required: No

Type: Integer

Update requires: No interruption

SpotMaxPrice

The maximum price per unit hour that you are willing to pay for a Spot Instance. If you leave the value of this property blank (which is the default), the maximum Spot price is set at the On-Demand price.

Required: No

Type: String

Minimum: 0

Maximum: 255

Update requires: No interruption

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